No Trick, Just Treat
by ShutUpAndPull
Summary: 'Castle Halloween Bash 2019 Entry' : (2-shot, AU, S4) Rick approaches Kate with a last-minute costume idea for his annual Halloween party and, fortunately for him, unfortunately for others, she agrees to it. Cue the party, cue the costumes, cue the treats.
1. Chapter 1

**AN: So, I've written this one on a whim, really. I realized I'd never taken part in this annual event, and not knowing when a thing might end up being one's final thing, well, I didn't want to miss out on the opportunity. Searching for Halloween prompts on the interweb, I stumbled upon one about a couple that wasn't yet a couple, a couples costume, and love. After that, I couldn't get our two as the two I have them portray in this piece out of my head. How sexy they would've been. **

* * *

**Chapter 1**

En route back to her desk that early morning, Kate turned the corner at the far end of the bullpen and found Rick and the boys huddled around her desk, giggling and exchanging high fives. In and of itself, it wasn't a scene out of the ordinary. She'd grown accustomed to the musketeers and their bromance, and to the antics it spawned.

That wasn't the first time she'd walked in on them engaged in such a boisterous confab over the past couple of days, though, and when they spotted her approaching and Javi's eyes hit her with a brazen head-to-toe sweep, it was clear something was going on, and that whatever it was, she'd been unknowingly roped into it.

"I don't know what the hell you're looking at me like that for, Espo, but I do know you should cut it out." She gladly accepted her customary morning cup of coffee from Rick's outstretched hand, brought it to her nose, and inhaled the sweet hint of vanilla. "What are you girls cackling about over here, anyway? By how pleased you seem to be with yourselves, a person might think maybe one of you got lucky last night. Personally, I don't like wasting my time on wild theories. That's Castle's neighborhood."

Rick scrunched up his face, despite the truth of it, and the three men carved a path, let her pass and settle behind the desk.

"Guess you didn't either," Javi bit back. "Grump." He caught the subsequent glance passed between Kate and Rick, dove headfirst into it like a kid into a wave. "Maybe the two of you could finally get on with it and help each other out with that. Just sayin'." His partner's eyes widened as he labored to hold in a burst of laughter. "Good luck, Castle," he said walking off. "If the grump goes for it, I'll show up this weekend as Bo Peep, and Ryan'll come as my sheep."

Kevin's head whipped around. "What? How the hell…" Grousing under his breath, he chased off after Javi, leaving Rick and Kate alone.

Rick dropped into his seat beside her desk, sipped from his morning blend in preparation. "Did you notice the-" He pointed with delight at her cup, at the bright orange pumpkin drawn across its curve in marker. "They let me do it while I was waiting in line. Nice touch, huh?"

Halloween was only a few days away. What more appropriate a time to be afraid of something, Kate thought, even if the fear stemmed only from the idea of asking him what the hell was going on. Honestly, she probably didn't really want to know, but, as she so often seemed to where he was concerned, she caved to curiosity.

"What do you want, Castle? It'll save me time and you the pain of trying to be cute if you just tell me."

A smug smile tugged at the corner of his mouth. "I assume the implication is that my cuteness usually comes naturally."

"Of course you do," Kate replied with a roll of her eyes. "Spill it."

Rick set his cup on the desk and dug into his jacket pocket, pulled out a folded square of paper. "Okay, well, you know, of course, Halloween is this weekend, as is my annual celebratory bash. Please, Katherine, this is a place of business. Try to contain your excitement," he cracked when her expression didn't shift an iota.

She gave him the side-eye, let it linger.

"I know this is last minute," he said as he opened the paper full, "and you probably already have a costume planned, as I did, but I came across this photo last night and I instantly thought of us, and I was hoping you might consider doing a… couples thing with me, instead."

_Couple_.

Even employed in innocent context the word sparked a flutter of Kate's heart. And it hadn't gone unnoticed that he'd wielded it gingerly, either, but, given where they currently were in their evolving relationship-or where he thought they were-that came as little surprise.

"Castle, I never said I was going to your party, first of all, and, second of all, we aren't a couple."

A paper cut across her fingertip was what the wait to have him felt like, one that never healed and throbbed whenever it was touched, and hearing those words out of her own mouth made it sting and burn.

"Yeah, because that's a reminder I need," he mumbled as he handed over the printout. "Look, you say you don't know if you'll be there and then you always show up. I just thought it might be fun if you showed up wearing that. Come on, Beckett, it's simple. You have the long hair now, not to mention the eyebrows and the sarcasm. You're practically her already."

Kate scrutinized the picture. It really would be simple, and she still had absolutely no idea what she was going to wear when she inevitably did show up. Lanie had suggested she don skintight pants and cherry-red lipstick and come as Sandy from _Grease_. Like that was going to happen, and certainly not now, after the way Javi had already been gawking at her.

"You probably should've started trying to grow the moustache as soon as last year's party was over, Castle," she teased. "It might've been ready by now."

He pushed back in the chair, unamused. "Oh, so you were planning on dressing up as a comedian then. I guess that would've been one way to guarantee you'd go unrecognized." Out of nowhere, he slapped his hand down on the desk. "Do this with me, please. I'll handle everything. My mother has a theater friend who said she'd help out with the clothes, not that it requires all that much, which is really the second best thing about it."

She slid the visual aid back his way, curled her fingers around her coffee. "What's the first?" she asked, noted his hesitation.

"That it's… something we can do together, obviously."

"You wanted to say Espo in a dress," she accused with narrowed eyes, and Rick appeared just as guilty as he, in fact, was. "That actually might just make it worth it."

**xxxx **

For being necessarily clothed in a costume-an enterprise that, year after year, proved aggravating above all else-Kate felt surprisingly comfortable. She'd even opted for the subway over a cab, given more looks than she'd received in a car crowded with a garish assortment of characters, and earned herself a correct first guess as to whom she was portraying for the evening from the doorman at Rick's building. All in all, the night had kicked off as well as it could've, and she still had Javi's and Kevin's getups to look forward to.

She found the door to the loft cracked open when she stepped off the elevator, the distinct and silly chorus of "Monster Mash" seeping out into the hallway, which provoked a hint of a smile. It wouldn't be the only time she'd hear it played over the next several hours, she knew; in fact, she'd probably hate it again by the time the party was over, but it was perfectly Rick to not care how silly it was, and that was, after all, much the reason she was as she had been for so long: in love.

Inside, the majority of the crowd was gathered around the kitchen, making small talk with makeup still fresh and wigs in place, but it was on Rick that her eyes landed and fixed. He was standing away from the others with his phone to his ear, his free hand fidgeting with the chain of the pocket watch laced through the buttonhole of his lapel.

It should've made her want to laugh, the moustache he'd secured just slightly askew above his lip, but that wasn't her reaction, at all. As she stood there watching him, she thought back on earlier days and how he'd often chosen not to make use of a razor, how much she'd quietly taken pleasure in that, and how sexy it'd been to her. Those days were few and far between now, but the reminiscence had her instantly buzzed, and without having swallowed a sip of his self-lauded green party punch.

Not that Kate had minded, but several minutes passed before Rick finally noticed her there. When he did, his entire face lit up and he hurried straight over, quitting his call along the way.

"Morticia, cara mia," he said embodying his role, drinking in all that was to be his play wife for the festivities. "I knew you'd look incredible, Detective. I do so love being right, and that it happens so often."

She cocked her head in disapproval. "And you've hidden yourself pretty well in this whole Mr. Addams thing, Castle. Too bad your ego's still showing." He didn't flinch with the bite. He just continued to stare at her, his lips gently parted. "What's wrong with you? Why are you-?

All at once, he seemed to plug back in.

"No, there's nothing wrong. I'm just happy you're here, that's all." Part of him truly wondered whether or not she'd show, even with the added incentive of her partners' impending humiliation. "May I get you a wonderfully ghoulish drink to start?" He offered a hand in request of hers, pressed his lips when she gave it, as Morticia's ever-bewitched husband would do, and led her toward the kitchen.

Save for a few familiar faces from the precinct, Kate didn't recognize most of the people there, she realized with a brief scan of the room, and not only because their identities were masked behind others. "I know Lanie's on her way here. She texted me a little bit ago. Where are Ryan and Esposito?" The pair was set to be the real entertainment of the night.

Rick presented her with a cup of punch that had a plastic eyeball bobbing around in it, ladled another for himself. "Oh, yeah, I was talking to Ryan when I saw you were here. He called to say they were smooshed in the back of a cab in traffic with Jenny, and that he was very hot and very itchy in his sheep head. He didn't appreciate that I was amused by all of that. Cheers to my queen of darkness."

They tapped cups and each took a gulp, Kate's lips puckering with the sour taste. "Now I remember why I never drink this stuff at these parties. This is disgusting, Castle." Meanwhile, he'd swallowed down nearly his entire share, and he couldn't have looked happier about it. "Of course he likes it," she remarked to herself. "Do you have anything stronger than this? Something that maybe doesn't glow in the dark?"

He reached into his pocket and pulled out a prop cigar, bit it between his teeth for a couple of seconds before curling it away in his fingers. "You know, for this brilliant idea of mine being thrown together at the last minute, I just have to say you really are wearing the hell out of that dress, and for granting me the wish, I have anything you want."

All the years, all the parties, but something on that night felt different. Kate felt different.

It was supposed to happen. She'd learned to stop pushing back against that reality, and even to dream about what it would be like when it did. But it wasn't supposed to happen yet. There was her mother's case and Dr. Burke and a wall and healing to be done. There was a plan. She had a plan. But she'd barely walked into the loft that night, barely spent five minutes with Rick, when this urge had come over her, and the power of it scared her.

"Maybe just a beer for now, actually," she replied. "I don't want to end up like Ryan last year." They both chuckled with the memory, because they were able to recollect it. Kevin, they imagined, wouldn't be able to say the same. "I'll see how things go."

"I'd steal the moon and stars from the sky for you if I could, cara mia, and bathe us both in beautiful darkness." He bowed. "I am at your service, always."

Gomez Addams set off for the refrigerator in his pinstripes, without a clue as to how well she understood Richard Castle would steal them for her, too, if ever she asked.


	2. Chapter 2

**Chapter 2**

"You two look _hot,_" Lanie gushed over Kate when Rick walked off to grab them all a round. "Please explain to me again how it is you haven't ended up like a couple of pretzels in a bed together yet. And don't you dare try to come at me with that 'We're just F-word' crap. That old song and dance has gotten F-word boring." She fanned herself with her hand, pushed her wild mermaid wig back away from her face. "You do see the way he's looking at you, right? The way his body keeps brushing up against yours? I am just saying. You should shift it into gear and swap treats to-night."

To herself, Kate wondered if it was actually her body doing the brushing, not Rick's, but, regardless, she challenged the observation wholly, as she always did.

"It does not, and he's just playing a part, Lanie. It's a character thing. We're supposed to be married."

"No shit," Lanie muttered. "Girl, I mean look at that. I don't know how you do it. Science should be studying your brand of willpower." She watched him stroll his way back over to them, the smile in his eyes, in his whole air. "I swear, if I didn't love you so much, I'd give it a go. Well, thank you kindly, Mr. Addams," she said, accepting the cup of punch he'd delivered.

"Gomez, please, and I assure you the pleasure's all mine, sea goddess." After handing Kate the bottle of beer he'd tucked into his jacket pocket for her, his hand casually curled around her back and settled at her waist. "What did I miss? What are you giving a go?"

Lanie spotted his fingers, flicked her brow at Kate, who, oddly-like touching one another wasn't a thing they rarely did-hadn't reacted to their placement.

"Sorry, Gomez, but these lips are sealed. Girl talk is for the girls only." She drank down a proper gulp of the electric-green punch and her eyelids scrunched shut. "Damn, Castle, what the hell? I probably have stuff in my lab that tastes less gnarly than this," she said with a grimace. "I am a sea goddess, and this sea goddess deserves better."

"You want me to-"

"No, I'll go. Who knows what you might try to bring me next. You two just keep doing… what you're doing." She turned back after shuffling off a couple of steps. "Oh, and you should definitely keep rockin' the moustache, Castle. You look all kinds of fine."

Rick snapped his head in Kate's direction. "Really, I do? What do you think?"

What a dangerous time to ask a dangerous question.

"I think it's crooked. But she was right."

"Yeah?" he asked, aglow in a fresh shade of tickled pink.

"Yeah, Castle, that sludge of yours is gnarly," she deadpanned, wrapping her lips around her bottle and then spitting it back out. "Holy shit, look at Esposito."

Javi and Kevin had just come through the loft's front door with Jenny in tow, and though they couldn't see Kevin's face hidden inside his costume, Javi looked deliciously miserable.

"As if I needed any more reasons to thank you for coming tonight, that comes walking through my door," Rick beamed. Kate gave a smug waggle of her fingers when Javi's scan of the room landed on her. "It's a good thing they came in a cab. Think about all the kids on the streets he could've left terrified in his wake."

The 12th gang crossed the room toward one another, met somewhere in the middle, Lanie included, who couldn't stop snickering.

"What's with the long face, Esposito?" Rick asked. "I see you found your lost sheep. You should be the happiest girl."

"This is so stupid," Kevin's muffled voice called out. "I can barely breathe in here."

Kate reached out and tugged on one of the blond curls of Javi's wig. "I wish Gates was here to see her prettiest detective."

"You guys are relentless," Jenny told the group before she leaned in to her husband. "Honey, can I get you something to drink or some grass to chew on or something?"

Everyone laughed. Even Javi cracked a grin, short-lived though it was. "I can't believe you caved," he grumbled at Kate. "Castle's making you soft, Beckett, you know that?" He paused, wandered over her with the same slow drift of his eyes that he had in the bullpen days before. "You do make a pretty caliente Addams, though, I gotta say."

"_Hey_," Rick and Lanie shot out in unison. Kate and Javi exchanged a soft smile.

"And you don't," he sneered at Rick. "What's that caterpillar on your face supposed to be, anyway?" Lanie sidled up to him, her colorful and formfitting ensemble earning its own once-over. "Speaking of caliente, you and that tail of yours want to show me where the booze is in this place, foxy mermaid?"

"Nice stick," she remarked suggestively of the makeshift shepherd's staff he'd employed as an accessory. "Let's go. You have to try Castle's punch." She looked back over her shoulder at Kate and Rick, tossed them a wink.

Rick turned to Kevin, who'd been standing there not saying a word for most of the conversation. His costume seemed to be about half a dozen sizes too small for his body, stretched tight in places it surely wasn't meant to.

"You find that thing in the kid's section, Ryan? Can you even see us right now?"

"Shut up, Castle," he hissed and swung to punch him in the arm but whiffed entirely.

**xxxx**

With audible relief, Kevin tugged the fuzzy sheep head off his shoulders, sent a band of sweat dripping from his hair down across his brow. His prison of fabric for the evening had been sized for a woman-and a slight one, at that-but he'd been able to find no alternative, thanks to his partner's big mouth and mere days to execute, and he was positively stifling in the thing.

No surprise, he was the first to raise his hand when, late in the night and after most of his guests had moved on to other engagements, Rick, advertised it was time, for anyone who remained and cared to partake, to go bobbing for apples.

"Hold this, Espo-Peep." Kevin shoved the matted mess of furry white against Javi's chest with a thud, caused the stick he was still carrying around to drop to the floor.

"What's up with you, bro? You think you've got it worse than this?" he asked pointing to his own frock-clad body. "I'm in a freakin' dress. I have a freakin' bonnet on my head."

Kevin stepped in so close he was spraying a mist of sweat with every word. "At least you can see where you're going,_ bro_. I've already broken one of Castle's ugly lamps and stepped on Jenny's toes twice."

"Um, excuse me," Rick jumped in in objection, "that lamp was a showpiece. Also, nice one with the 'Espo-Peep' thing. How did I not think of that?" Javi practically bore his teeth and snarled. "But, okay, let's get back to apples. Come on, Ryan, you're first up."

He'd bought a plastic kiddie pool for the floor, set a table in it and a metal basin on top of that. Kevin stepped in for his turn, his cheeks dewy and rosy with heat.

"The rules are very simple," Rick told him. "You have one minute in the tub. No hands. You get one apple, you get a prize. You get more than that, the prizes get better."

"Like that'll happen," Javi taunted.

Rick pulled out his pocket watch, waited for the wand to tick to a desirable position, and uttered the magic words. "On your mark, get set, go!"

Most gathered cheered Kevin on, and though he played along with the game of it, all he really wanted at that point was the cold water on his face, which felt more satisfying than winning any prize could. He did manage to successfully snag one apple for his meager effort, and collected his full-size 3 Musketeers bar from Rick in exchange.

"Nice job, honey," Jenny cooed, planted a kiss on his cheek with her red Raggedy Ann lips.

"Oh yeah, honey, you're such a baaaaadass," Javi said, taking another jab. "One apple, dude, really? I've seen little kids do better than that."

Rick sought another volunteer, heard Kate's voice return from somewhere off in the distance. She'd been standing alone, away from the others, her focus precise but her brain a fireworks display of thoughts.

"I'll go," she said and came forward, collecting the hair of her stringy wig and securing it with a band she'd worn around her wrist.

"Well, well, all, it appears the NYPD's finest-and my dear Halloween wife-is up for the challenge," Rick announced. "You do surprise me, Detective," he added when she slid by.

Honestly, she was the last person at that party he'd ever have thought would jump in, and it wouldn't have been overstating to say her willingness to do so had him titillated in a flash.

"Pretty weak, Kev," she needled as she stepped into the pool and up to post. "And don't even think about pawning off any of those garbage candy bars on me, Gomez, if they even deserve to be called that."

"So, she's gorgeous, surprising, and feisty. Bring it on, Morticia. Let's see what you've got, and if your achievement is worthy, I'll see what I've got."

Kate had never bobbed for an apple in her life, and she had no idea why the hell she was doing so now, even as she plunged her face into the water, but it turned out beginner's luck was on her side, and she captured three with her teeth, a thing even Rick Been-There-and-Done-That Castle couldn't boast about.

With a deserved round of applause, Rick gave her a hand towel to dry off. "You should show off more often, Detective. Pluck looks good on you. I guess I'm going to have to dig deep into my bag of treats."

"I guess you are, Castle. While you do that, I'm going to go use the bathroom and fix myself up."

"Use mine," he said. "Through the office, into my bedroom, and hang a left. But, trust me, from where I'm standing, there isn't a thing to be fixed."

It was neither the time nor the place. She knew that as she eyed herself in the mirror, wiped away the smudges of black eyeliner and mascara the water had left behind. And yet, the voice she continued to hear in her head was her own, the one asking her what harm would come of a taste when she'd soon be allowing herself a full feast, anyway.

Over the course of the night, that voice had been growing louder, crying out at every passing glance or graze of a hand or sweet word. Now, it was almost deafening.

"Hey." Rick was waiting for her when she emerged. He was sitting on the end of his bed with a large, plastic pumpkin propped up beside him.

"Did you ditch your guests and sneak in here to stuff your face with second-rate chocolate?" She could hear everyone out in the great room as they sounded off for another bobber. "I thought you might go next, try to show me up," she said, leaning against the doorframe.

"I owed you a prize, Detective. I pay my debts." He dipped his hand into the pail. "Showing you up can wait a few minutes," he said with a pop of his brow.

_He's sitting right there_, she heard the voice nudge. _What are you waiting for?_

"Castle," she began before a thoughtful pause. "Do you ever wish you could be someone else, even if it was just for a little while?"

His fingers quieted, and he gazed at her quizzically.

"I'm someone else right now, Mrs. Addams."

Kate pushed out a breath, shook her head gently. "That's not-"

Rick noted her seriousness, gave her the truest response that came. "Okay, if I was someone else-for whatever reason-would I still know you? Would you still be in my life?"

That wasn't the point, of course, but, then again, he couldn't possibly know what the point was.

"If not, the answer is no, because I wouldn't want any kind of life that doesn't have you in it."

"How do you do that?" she wondered aloud. "How do you say things that aren't easy so easily, Castle?"

"I drank the punch," he joked and won a giggle. "Is that something you wish for, Kate, to be someone else? I hope you don't," he answered when she didn't.

Nervous and looking half a mess, she walked over to him. "So, what've you got for me?"

He got very excited very quickly.

"What you're looking at here is my private stash of prime treats. I share these babies with no one, not even Alexis or my mother. In here are the Cadillacs of candy bars, and this is your lucky night, Beckett. You get to reach your pretty little hand in and go fishing for three of them. Yes, you heard me right. I have decided I'm willing to part with a few, but only for you."

Rick gripped the pail with both hands, instructed her to close her eyes and to choose. When she opened them, she found two bars she'd never heard of alongside a Skor.

"What's that face for?" he asked of her apparent displeasure. "That's gold-level stuff."

"Skor, Castle, really?"

"Yes, really. They are a buttery toffee delight. But, I suppose if delightful things don't meet with your approval, drop it back in and pick a different one. I will be perfectly happy to gobble up your foolish castoff."

She had to do it. She had to do it now. It felt like some kind of imperative, some necessity of her lips that she have his.

"I have another idea." She dropped the keepers onto the bed and the Skor back into the pumpkin, took a step nearer and leaned in, her hands braced on his knees. "How about instead of me taking another, you let me take something else and we call it even."

Rick cleared his throat. Her proximity had him completely shaken.

"Did Ryan put you up to this? Is this some kind of a trick, because if it is, it's already a very cruel one?"

"Tricks are your thing, Castle, not mine," she replied and pressed her mouth to his, tentative at first, but melting into him when he beseeched more.

When they parted, he was panting with the thrill of it. "You got the apples and I won the prize. How the hell did that happen?"

Kate stood upright, freed her wig from its restraint. "Must be your lucky night, too, Castle. I need a drink. Want to go back out there?"

The only move he made was to cross one leg over the other.

"I'm, um, I'm definitely going to need a minute," he said. "Oh, hey, you forgot your-"

"We'll come back for them later," she said and walked out. For them and, maybe, more.


End file.
